I think you've pretty much nailed it - it comes down to whether you care more abut bigger wheels or more storage space? Or whether you really prefer the styling of one or the other...

As for the build quality I'm afraid I cannot say - my HD200 is certainly put together very well, but VS owners don't complain either. Some of them did complain about high fuel consumption - it seems a bit hit and miss with this model. Both are covered by the same warranty in our market.

VS125 is certainly very popular here but VS150 only came very recently so there isn't much info out there yet. As for HD, we only ever had the 200 model (which is actually 170cc).